Recently, a graphene wiring structure using graphene wires instead of metal wires has received much attention. Since graphene has a quantization-conduction characteristic (ballistic conduction characteristic) like a carbon nano-tube and conducts electricity by quantization, it is advantageous in comparison with electrical conduction of a long-distance wire. Further, the graphene wiring structure itself is an extremely thin film and can be formed by use of a CVD method. Therefore, a graphene wire has a high degree of matching with respect to a device wire formation process.
Further, graphene has a property of being able to be selectively grown from a catalyst metal. Therefore, the graphene wiring structure is preferably formed by combining the catalyst layer with graphene, and a graphene sheet preferably contains a large number (N number) of hexagon lattice structures of graphene. However, since the graphene sheet width is rate-controlled according to the width of a wire in the graphene wiring structure grown in a plane on a catalyst metal, the N number is restricted. Therefore, if the width of the wire becomes narrow and the N number decreases, the structure is strongly influenced by the edge effect on the graphene end portion. Then, modulation of the graphene band structure and scattering of carriers at the edge portion become significant and the wiring resistance increases.